The following paragraphs are not an admission that anything discussed in them is prior art or part of the knowledge of persons skilled in the art.
Solid phase microextraction (SPME) is an approach for sample preparation that may be used in various analytical methods. SPME devices include an extraction coating present on a support. The extraction coating includes adsorptive particles, which may have different geometries. Exposure of the SPME device directly into a matrix or into its headspace, for a certain period of time, extracts and enriches analytes contained in the sample matrix.
The SPME process is governed by the partitioning of analytes from the matrix onto or into the extraction phase, and extraction efficiency of an analyte depends on the analyte's affinity toward the adsorptive particles present in the extraction coating.
After extraction and enrichment of the analytes onto or into the extraction phase, the SPME device may be placed in an analytical device where the analytes are desorbed and analyzed.
Adomaviciute et al., “In-Groove Carbon Nanotube Device for SPME of Aromatic Hydrocarbons”, Chromatographia, 2008, 67, 599-605 teaches a SPME fiber with a coating incorporated into a groove of a stainless steel rod and mounted inside an external needle.
U.S. Patent Publication 2014/0220701 teaches an extractor device that has a tip which protects the extractor during penetration into a separating layer.